System Sensor DH500ACDC specifications Installation for Ducts Less Than 8 Feet Wide

Figure 4. Tube mounting configurations with varying air flow direction and orientation of detector housing. Vertical as well as horizontal mounting is acceptable.

DOTS INDICATE POSITION OF

SAMPLING TUBE HOLES

AIR FLOW	AIR FLOW
	DIRECTION
DIRECTION

DETECTOR HOUSING

INLET

TUBE

DETECTOR

HOUSING

A.		B.
EXHAUST	EXHAUST	INLET
TUBE	TUBE	TUBE

HORIZONTAL MOUNTING OF HOUSING

EXHAUST
TUBE	DETECTOR
	HOUSING

	EXHAUST
AIR FLOW	TUBE		AIR FLOW
DIRECTION			DIRECTION
	INLET	INLET
DETECTOR	TUBE	TUBE	D.
HOUSING	C.

VERTICAL MOUNTING OF HOUSING

H0109-00

A. Installation for Ducts Less Than 8 Feet Wide

1.If the inlet tube is longer than the width of the air duct, drill a 3/4-inch hole in the duct directly opposite the hole already cut for the inlet tube.

If the inlet tube is shorter than the width of the air duct, install the end cap into the inlet tube as shown in Figure 3.

2.Slide the inlet tube into the bushing located in the center of the duct housing. Position the tube so that the arrows point into the air flow.

3.Secure the tube flange to the housing bushing with the two #6 self-tapping screws.

4.For tubes longer than the width of the air duct, the tube should extend through the opposite side of the duct. If there are more than 2 holes in the section of the tube extending from the duct, select a different tube length using Table 1. Otherwise, trim the end of the tube pro- truding through the duct so that 1 to 2 inches of the tube extends outside the duct. Plug this end with the tube end plug and tape closed any holes in the protruding section of the tube. Be sure to seal the duct when the tube protrudes.

5.Any inlet tube over 3 feet long must be supported on the opposite side of the duct detector housing.

WARNING

In no case should more than 2 air inlet holes be cut off the tube. There must be a minimum of 10 holes in the tube exposed to the air stream.

B. Installation for Ducts More Than 8 Feet Wide

NOTE: To install inlet tubes in ducts more than 8 feet wide, work must be performed inside the air duct. Sampling of air in ducts wider than 8 feet is accom- plished by using the ST-10 inlet sampling tube.

Install the inlet tube as follows:

1.Drill a 3/4-inch hole in the duct directly opposite the hole already drilled for the inlet tube.

2.Slide the inlet tube into the bushing located in the center of the duct housing. Position the tube so that the arrows point into the air flow. Secure the tube flange to the housing bushing with the two #6 self-tapping screws.

3.From inside the duct, couple the other section of the inlet tube to the section already installed using the 1/2- inch conduit fitting supplied. Make sure that the holes on both of the air inlet tubes are lined up facing the direction of air flow.

4.Trim the end of the tube protruding through the duct so that 1 to 2 inches of the tube extends outside the duct. Plug this end with the tube end plug and tape closed any holes in the protruding section of the tube. Be sure to seal the duct when the tube protrudes.

5.Any tube (over 3 feet long) that doesn’t protrude through the duct (on the side opposite the housing) must be sup- ported by other means.

NOTE: An alternate method to using the ST-10 is to use two ST-5 inlet tubes. Remove the flange from one of the tubes and install as described above. After the installation, use electrician’s tape to close off some of the sampling holes so that there are a total of 12 holes spaced as evenly as possible across the width of the duct.

NOTE: Air currents inside the duct may cause excessive vibration. This vibration can slowly open the seal around the tube and permit air to escape. To prevent this from occurring, a 3-inch floor flange,

D500-07-00 4 I56-432-11R